1. Field of the Invention
The present invention relates to bandages; and, more particularly to releasable bandages, such as wound dressings, gauze retainers or splints that remain securely attached during use, but can be painlessly released upon demand.
2. Description of the Prior Art
Bandages are well known in the art and are used for various medical applications and sports protection. Sterile bandages marketed under well-recognized trade names, such as ‘Band-Aid’, ‘Cural’ and the like, that provide secure attachment of the bandage's adhesive portion to bare skin adjacent to a wound. A sterile wound-covering pad contacts the wound. More recently, adhesives have been developed for bandages that do not peel off even when the bandage is wetted by sweat or swimming activity. The corners of the bandages are oftentimes shaped to prevent easy release of the bandage. All these developments prevent easy removal of the bandage, especially when the area of the skin is covered with hair. Bandage removal is typically so painful that most patients and doctors remove the bandage by pulling sharply, as fast as possible, to minimize the duration of pain. No solution is presently available that allows easy, pain-free or reduced-pain removal of a bandage. The pain problem becomes more severe as the size of the bandage increases, as is the case for splint restrainers or gauzes.
Several patents detail construction of bandages and selection of adhesives, which improve skin adhesion. Some patents address the shape of the bandage so that the edges do not readily peel off. Some patents provide a covering that prevents the wound-contacting portion of the dressing from sticking to the wound, thereby reducing pain of bandage removal. None of these patents addresses the problem of pain associated with removal of the adhesive tape that retains the bandage against the skin.
Several patents address use of release layers normally coated on the side of a bandage opposed to the adhesive coated surface, enabling the peeling of a wound adhesive tape. This release layer is applied to the backside that is opposed to the adhesive side of the polymeric tape and has nothing to do with the release of the tape from the skin. These tape release compositions are not discussed. In fact, the presence of this release layer on the skin is not useful since the tape will no longer adhere to the skin.
U.S. Pat. No. 4,140,115 to Schonfeld discloses pressure sensitive adhesive compositions for coating articles to be attached to skin. Skin damage, i.e., the stripping of tissue cells from the stratum corneum, caused by removal of a backing material which has been held in adherent contact with a skin surface by means of a pressure sensitive adhesive composition coated on the backing material, is markedly reduced by incorporation of about 4 to 20% by weight of an unreacted polyol uniformly dispersed in the water-insoluble pressure sensitive adhesive mass. Suitable polyols include polyethylene glycol and polypropylene sorbitol monolaurate. The unreacted polyol is always present in the adhesive reducing the tackiness of the adhesive and easy release of the adhesive tape is achieved at the expense of the adhesive properties.
U.S. Pat. Nos. 4,693,776 and 4,732,808 to Krampe et al. disclose macromer reinforced pressure sensitive skin adhesive sheet material. A skin adhesive coated sheet material is provided which is coated with a polymer that exhibits an enhanced level of initial adhesion when applied to skin but resists objectionable adhesion build up over time. The skin adhesives are comprised of a macromer reinforced acrylate copolymer, which has a creep compliance value at least about 1.2×10−5 cm2/dyne. A stable chemical complex of iodine, iodide and a pressure-sensitive adhesive is also provided wherein the adhesive has a creep compliance value of at least about 1.0×10−5 cm2/dyne measured when the adhesive composition is substantially free of iodine. The adhesive contains a monomeric acrylate or methacrylate ester of a non-tertiary alcohol, at least one ethylenically unsaturated compound copolymerizable with monomeric acrylate or methacrylate ester and a macromer. The addition of these macromer is always present in the adhesive, which degrades as a function. Easy peel of the adhesive layer does not occur until this degradation has occurred and the bandage cannot be removed without pain at any time selected by the user.
U.S. Pat. No. 5,412,035 to Schmitt et al. discloses pressure-sensitive adhesives. Pressure-sensitive adhesive compositions containing a crystalline polymeric additive having a molecular weight of less than 25,000 and a melting point greater than 23 degree C., preferably 30 to 60 degree C., coated on a flexible backing. The presence of the additive causes the pressure sensitive adhesive to lose adhesive strength when heated to the melting point of the additive. The base resin of the pressure sensitive adhesive is a polyacrylate or a styrene/butadiene copolymer. The additive, which is a side chain crystallizable polymer, is present in an amount ranging from 1 to 35%. Heat has to be applied to release this bandage. Application of heat to a wound is extremely painful and may, in the worst case, retard the healing process of the wound.
U.S. Pat. No. 5,947,917 to Carte et al. discloses an adhesive bandage or tape. A water resistant, flexible, dermal adhesive product for conformable topical application to human skin, the dermal adhesive product comprising a backing sheet having an adhesive for removably adhering the sheet to the skin, wherein the adhesive is a highly crosslinked pressure sensitive adhesive composition comprising the polymerization reaction product of about 75% to about 95% of a mixture of at least two alkyl acrylate or methacrylate esters, about 1% to about 10% ethylenically unsaturated carboxylic acid, and about 10% to about 20% vinyl lactam, by dry weight of solids, preferably about 80% to about 90% of a mixture of at least two alkyl acrylate or methacrylate esters, about 2% to about 5% ethylenically unsaturated carboxylic acid, and about 10% to about 20% vinyl lactam, by dry weight of solids. This water resistant adhesive for bandage is very effective in attaching to the skin of the user; but is difficult to peel without undue pain.
U.S. Pat. No. 6,077,589 to De Carvalho discloses adhesive tape. The adhesive tape substratum is embossed to provide an increased apparent thickness with protuberances and projections. The adhesive contacts the skin only at the apexes or extreme points of projections, leaving the remainder of the skin substratum distant. This arrangement allows free circulation of air and water vapor near to or around the non-adhered regions. The adhesive is said to be easier to peel, due to its limited contact area with the skin; but does not allow secure retention of the bandage.
U.S. Pat. No. 6,368,687 to Joseph et al. discloses a low trauma adhesive article. A low trauma pressure-sensitive adhesive coated substrate comprising a sheet material, tape or laminate structure designed to adhere to skin or like surfaces. The pressure-sensitive adhesive layer of this adhesive coated substrate is a fibrous adhesive layer generally having a basis weight of from 5 to 200 g/m2 applied to a conformable backing or substrate. The fibrous adhesive layer has a textured outer face and persistent porosity between discrete adhesive fibers. Generally, the fibrous adhesive layer has a MVTR (measured by ASTM E 96-80 at 40° C.) of at least 1000 g/m2/day, preferably at least 6000 g/m2/day. The adhesive fibers comprise polyalphaolefin adhesive or acrylate pressure-sensitive adhesive. These fibers have to be bonded to the backing by means other than relying on the pressure sensitive adhesive coating applied to the fibers. The easy peel of these fibers is only due to the limited contact between the fibers and the skin surface. This limited skin contact feature also limits the adhesive property of the backing strip to the skin, preventing secure attachment of the bandage.
U.S. Pat. No. 6,566,577 to Addison et al. discloses wound dressings having low adherency. The wound dressings are of the island type, having as adhesive-coated backing sheet and an absorbent island supported on the backing sheet. The island comprises a layer of liquid absorbent material enclosed in an envelope of textured perforated ethyl methyl acrylate thermoplastic film. The film presents a ribbed or embossed perforated surface having low adherency to the wound. The film island at the rear surface of the envelope is perforated and smoothed to provide good attachment to the backing sheet with controlled water vapor transmission rate. The liquid absorbing island of the wound dressing has low adherency to the wound due to the presence of rib textured perforated thermoplastic film. The backing sheet that carries the absorbing island is adhered to skin to retain the wound dressing and no disclosure is provided for easily peeling this backing sheet from the skin with undue pain.
U.S. Pat. No. 6,743,964 to Yoshida et al. discloses a pad and adhesive bandage. A pad has an approximate-quadrangular portion and approximate-arched portions attached to both lateral sides of the approximate-quadrangular portion. All the periphery of the pad is sealed with ultrasonic treatment. L represents the length of the approximate-quadrangular portion in the direction parallel to the lateral axis, S represents the length of the approximate-quadrangular portion in the direction parallel to the vertical axis and R represents a radius of said approximate-arched portion. The geometrical relation between L, S and R satisfies following relations.
0.5S<or =L<or =4S between L and S;
0.5S<or ═R<S between S and R.
The pad prevents peeling-off from four corners thereof and intrusion of water. This is a geometrical relationship between the dimensions of the elements of the adhesive pad when exposed to moisture. This disclosure does not suggest a method or means for enabling a bandage to be peeled easily without pain.
U.S. Pat. No. 6,747,183 to Siegwart et al. discloses an adhesive bandage with improved comfort and fit. An adhesive bandage having a backing material; an adhesive applied to at least one second major surface of the backing material; and a wound contacting a pad secured to the backing by a portion of the adhesive. The bandage has a tapered portion and a non-tapered portion with rounded edges. The length of the tapered portion of the bandage ranges from about 30% to about 70% of the total length of the bandage. The adhesive to bond the wound-contacting pad includes a hot melt adhesive or styrenic block copolymers and tackifying resins, or ethylene copolymers, including ethylene vinyl acetate copolymers. The adhesive for the bandage portion includes acrylic based, dextrin based, and urethane based adhesives as well as those based on natural rubber or synthetic elastomers including amorphous polyolefins, for example, amorphous polypropylene. The comfort of the adhesive bandage is due to the geometrical shape of the adhesive ends and does not allow easy painless removal of the bandage.
U.S. Pat. No. 6,942,683 to Dunshee discloses a wound closure system and method. The system uses a flowable adhesive together with wound closure such as wound bridge. The skin paint includes 1-40% of a siloxane-containing polymer; 60-99% of an Alkane-Based Siloxane Polymer Reaction Solvent; and 0-15% of adjuvants.
U.S. Pat. No. 6,946,177 to Abe et al. discloses an adhesive composition and adhered structure, which can be thermally peeled with ease. The adhesive composition contains (i) from 55 to 95 wt. % of a tackifying polymer and (ii) from 4 to 40 wt. % of a crystalline polycaprolactone polymer based on a total weight of the composition. The tackifying polymer is cross-linked polymer that is compatible with the polycaprolactone which melts upon application of heat allowing easy peel of the adhesive. Application of heat also heats the wound in addition to heating the adhesive ends of a bandage, which is extremely painful and damaging to the wound. After peeling, the melted polycaprolactone is retained on the skin, which may cause irritation of skin.
Notwithstanding the efforts of prior art workers to construct a bandage that adheres to the skin securely in wet and dry conditions, these progressive developments have inherently resulted in bandages that are more difficult to peel of the skin especially when the user of the bandage has hair on the skin, resulting in extreme pain. Compositions and structures that decrease adhesion due to the incorporation of monomeric precursors of polymers or the geometrical approaches that limit the area of contact of the adhesive with the skin also compromise the overall adhesion of the bandage, resulting in inferior products. There remains a need in the art for a flexible bandage that adheres well to the skin and is easily removable from the skin at will without causing excessive pain to the user. This need has been exacerbated by the inherent difficulty in creating an bandage adhesive that bonds well and, at the same time, can be readily removed with minimal pain during peeling of the bandage away from the skin.